Current snowpack could lead to a dangerous avalanche season, expert says

(Jackson, Wyo.) - Jackson Hole hasn't gotten a significant amount of snow
yet this year, but the little that we have gotten combined with the cold
temperatures could be a recipe for a dangerous avalanche year.
Bob Comey, avalanche forecaster for the Bridger-Teton National Forest
Avalanche Center, met with Buckrail to help us understand the current snow
conditions.
Jackson Hole received 20 - 30 inches of snow in the high country in
November, but we haven't gotten much snow since November 20.
"If you have shallow snow depth and cold temperatures, there is a process
that occurs on the ground that changes the crystal structure of the
snowpack to what we call faceted show, which is sugar snow," said Comey.
"It is very weak. It isn't a problem right now because there isn't a load
on it."
Comey said that it could be a problem when we get snow because it is
potentially set up for good sliding layers and weak structures at the base
of the snow pack.
"There are all different scenarios. We don't know until it happens," he
said. "A huge dump of snow right now would result in a lot of avalanche
activity. But if it was big enough, it would likely settle and give it
enough strength."
There are four types of avalanche problems:
- Wind slabs: A wind slab is a the release of a cohesive layer of snow
formed by the wind.
- Storm Slabs: A storm slab is the release of a soft cohesive layer of
new snow that breaks within the storm snow or on the old snow surface.
- Persistent Slabs: A persistent slab is the release of a cohesive layer
of soft to hard snow in the middle to upper snowpack, when the bond to an
underlying persistent weak layer breaks.
- Deep Persistent Slabs: Deep persistent slabs are when there is a
release of a thick cohesive layer of hard snow, when the bond breaks
between the slab and an underlying persistent weak layer, deep in the
snowpack or near the ground.
The Colorado Avalanche Information Center recently did research where they
looked at 90 avalanche fatalities over 15 years in Colorado. The study
showed that the most fatalities are the result of persistent and deep
persistent slabs.
"Between those two types of avalanches [persistent and deep persistent],
they kill almost 85 percent of the people," said Comey.
According to Comey, based on the current snowpack, Jackson Hole is on track
to have persistent slabs and then later in the year to have deep persistent
slabs. He recommends looking at the daily avalanche forecast
, and paying special attention to the
avalanche problems.
"If you go to that on a daily basis and you see persistent slabs or
persistent deep slabs in the problems, then that should be a red flag for
you," he added. "You really need to bone up on your avalanche class and
avalanche education to really know what persistent slabs are and why they
are so dangerous."
The Bridger-Teton Avalanche Center forecasts a large area from Togwotee
Pass all the way down to Grey's River. Comey said that some areas are
looking more risky than others already.
"We are seeing the risk for persistent slabs where the snow is shallower.
We are seeing it in the Togwotee Pass area, and down south in the Greys
River area," said Comey. "In the Tetons, right now we are seeing places
where the snow is 20-30 inches deep, so the risk is not as severe."
Comey said that snowmobilers are at a higher risk for triggering an
avalanche than backcountry skiers because they cover more area and are
heavier triggers.
The key is to educate yourself on these types of avalanches and how to
manage them.
"You might have to back it off and stay out of the avalanche terrain," he
said. "There is plenty of good riding and skiing without exposing yourself
to avalanche hazards. The whole goal is to come home."
While these are Comey's predictions based on his experience and knowledge
of the snowpack, it is difficult to know what will happen without a crystal
ball.
"We just have to wait and see," he said.
*Feature Photo: Bob Comey, forecaster for the Bridger-Teton National Forest
Avalanche Center / Pitchengine Communities *
#buckrail #news

Current snowpack could lead to a dangerous avalanche season, expert says

(Jackson, Wyo.) - Jackson Hole hasn't gotten a significant amount of snow
yet this year, but the little that we have gotten combined with the cold
temperatures could be a recipe for a dangerous avalanche year.
Bob Comey, avalanche forecaster for the Bridger-Teton National Forest
Avalanche Center, met with Buckrail to help us understand the current snow
conditions.
Jackson Hole received 20 - 30 inches of snow in the high country in
November, but we haven't gotten much snow since November 20.
"If you have shallow snow depth and cold temperatures, there is a process
that occurs on the ground that changes the crystal structure of the
snowpack to what we call faceted show, which is sugar snow," said Comey.
"It is very weak. It isn't a problem right now because there isn't a load
on it."
Comey said that it could be a problem when we get snow because it is
potentially set up for good sliding layers and weak structures at the base
of the snow pack.
"There are all different scenarios. We don't know until it happens," he
said. "A huge dump of snow right now would result in a lot of avalanche
activity. But if it was big enough, it would likely settle and give it
enough strength."
There are four types of avalanche problems:
- Wind slabs: A wind slab is a the release of a cohesive layer of snow
formed by the wind.
- Storm Slabs: A storm slab is the release of a soft cohesive layer of
new snow that breaks within the storm snow or on the old snow surface.
- Persistent Slabs: A persistent slab is the release of a cohesive layer
of soft to hard snow in the middle to upper snowpack, when the bond to an
underlying persistent weak layer breaks.
- Deep Persistent Slabs: Deep persistent slabs are when there is a
release of a thick cohesive layer of hard snow, when the bond breaks
between the slab and an underlying persistent weak layer, deep in the
snowpack or near the ground.
The Colorado Avalanche Information Center recently did research where they
looked at 90 avalanche fatalities over 15 years in Colorado. The study
showed that the most fatalities are the result of persistent and deep
persistent slabs.
"Between those two types of avalanches [persistent and deep persistent],
they kill almost 85 percent of the people," said Comey.
According to Comey, based on the current snowpack, Jackson Hole is on track
to have persistent slabs and then later in the year to have deep persistent
slabs. He recommends looking at the daily avalanche forecast
, and paying special attention to the
avalanche problems.
"If you go to that on a daily basis and you see persistent slabs or
persistent deep slabs in the problems, then that should be a red flag for
you," he added. "You really need to bone up on your avalanche class and
avalanche education to really know what persistent slabs are and why they
are so dangerous."
The Bridger-Teton Avalanche Center forecasts a large area from Togwotee
Pass all the way down to Grey's River. Comey said that some areas are
looking more risky than others already.
"We are seeing the risk for persistent slabs where the snow is shallower.
We are seeing it in the Togwotee Pass area, and down south in the Greys
River area," said Comey. "In the Tetons, right now we are seeing places
where the snow is 20-30 inches deep, so the risk is not as severe."
Comey said that snowmobilers are at a higher risk for triggering an
avalanche than backcountry skiers because they cover more area and are
heavier triggers.
The key is to educate yourself on these types of avalanches and how to
manage them.
"You might have to back it off and stay out of the avalanche terrain," he
said. "There is plenty of good riding and skiing without exposing yourself
to avalanche hazards. The whole goal is to come home."
While these are Comey's predictions based on his experience and knowledge
of the snowpack, it is difficult to know what will happen without a crystal
ball.
"We just have to wait and see," he said.
*Feature Photo: Bob Comey, forecaster for the Bridger-Teton National Forest
Avalanche Center / Pitchengine Communities *
#buckrail #news